Balston’s Pygmy Perch

Posted on Dec 23, 2014

Balston’s Pygmy Perch

Balston's Pygmy Perch (Nannatherina balstoni) (S Beatty)

Balston’s Pygmy Perch (Nannatherina balstoni) (S Beatty)

Balston’s Pygmy Perch (Nannatherina balstoni) which is endemic to Western Australia is a small, freshwater fish with a maximum length of 9cm. The fish has a brownish coloured black and silver belly usually with a prominent brown middle stripe running along its side and a series of vertical brown bars giving it a cross-thatched appearance.

Habitat and Life Cycle

It lives commonly in shallow water, preferring tall sedge thickets and inundated riparian vegetation and is generally found in coastal peat flats in the south western region that extends from Margaret River to Two People’s Bay. However it’s range has been severely fragmented, as it used to be found in waterways extending to Moore River to the north of Perth. This fish species can live up to three years but usually only lasts for about a year, and typically die after their first spawning season.

Conservation Status

The species is federally listed as vulnerable as its range has been severely contracted (by about 50%) most likely due to salinisation of its habitat. The limited geographic distribution and severe fragmentation of the populations, combined with the range of threats operating in the areas occupied by the Balston’s Pygmy Perch makes the geographical distribution of the species precarious for its survival.


Threats to this species include loss of habitat due to rural and urban development, habitat alteration due to salinisation which is most likely the major cause of declines of this species, eutrophication and changes in flow regimes as well as to activities such as ground water extraction, mining operations, and the introduction of exotic fish including Rainbow Trout, Eastern Mosquitofish and Redfin Perch.

Balston’s Pygmy Perch and Climate Change


SWCC Strategic Priority

The Balston’s Pygmy Perch is identified as a first order priority asset within SWCC’s NRM Strategy under the Aquatic Biodiversity theme.


There are 2 current projects occurring for this species, the first with Murdoch Freshwater Fish group who are doing research into the degree of population decline, to identify key refuge habitats, to undertake barrier mitigation activities, feral fish control and awareness raising activities. The second project is with the Warren Catchments Council who is undertaking conservation measures at historical sites where the species have occurred such as bank stabilisation and riparian restoration.


Submit a Comment

Your email address will not be published.